Feature perimeter support for dividers, and top product quality at a very economical price. Unique self-stabilizing dividers feature interlocking wings at each divider junction allowing rigidity of the unsupported sections - no more divider warp, wiggle or "give". Divider boxes feature uniform wall thickness. Constructed of high-density polyethylene for strength and light weight. Capacity to 40 lbs. per container. Bottom container will support 250 lbs. when stacked. Covers are clear, with horizontal dividers neutral. Can be subdivided with vertical dividers into 1-1/8" sq. minimum size compartments or multiple thereof. The grooves are 3/16" wide. One set of cardholder snaps included on all models, must purchase clear vinyl cardholder separately. Covers: Two styles are available. Insert cover (lays inside box on stacking ridge); snap-on covers; both are transparent plastic.